Conductivity relaxation studies on sol-gel-derived Li₂O-SiO₂ glasses by a heterogeneous conductor model

Abstract

Conductivity relaxation spectra of sol-gel-derived glasses in the system Li₂O (1-x) SiO₂, with x varying from 0.15 to 0.25, have been analyzed using a heterogeneous conductor model. The latter comprises diagonal layers of phases, one of them being rich in alkali ions and the other deficient in the same. Satisfactory agreement between the experimental data and the theoretical curves has been obtained over the frequency range 100 Hz to 1 MHz. The Kohlrausch-Williams-Watts (KWW) exponent, β, has been calculated from the conductivity spectra for all the glasses. The sol-gel-derived glasses have β values smaller than those obtained in the case of the corresponding melt-quenched ones. The β value is found to be correlated to the conductivity fluctuation in the alkali-rich phase.